Security constrained optimal power flow method based on power flow transfer relation

Abstract

The invention discloses a security constrained optimal power flow method based on power flow transfer relation. The method is characterized by establishing active power flow transfer relationship before and after fault based on anticipated fault analysis; describing fault-state branch active power flow into a ground-state branch active power flow function, so that the fault-state branch active power flow constraint is described as ground-state branch active power flow linear inequality constraint; and carrying out grouping on parallel circuits and parallel main transformers, and reducing the scale of monitored branches by utilizing power flow distribution relationship of branches in each group, and carrying out filtering on the fault-state branch active power flow constraint by utilizing the characteristic that short-time flow capacity of a device is obviously larger than long-term flow capacity thereof to minimize the calculation scale of the SCOPF problem as far as possible. The method has a good effect.

Description

technical field [0001] The invention belongs to the field of optimal dispatching of power systems, and relates to a safety-constrained optimal power flow method based on power flow transfer relations. Background technique [0002] Since the real-time automatic processing of power system faults still has great technical difficulties, the focus of safe operation of the power grid is to prevent the consequences of accidents. In order to avoid cascading failures caused by predicted disconnection and allow sufficient time for operators to deal with accidents, it is necessary to properly control the power flow during normal operation of the power grid to ensure that the credible predicted disconnection will not cause the power flow of power equipment to exceed Its short-term allowable carrying capacity. Security Constrained Optimal Power Flow (SCOPF) adds reliability constraints to the optimal power flow model, which can better guarantee the safe and reliable operation of the pow...

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Problems solved by technology

[0003] For large-scale power systems, due to the large scale of expected fault sets, if all expected fault states are modeled in detail and their reliability constraints are considered, the calculation scale of the SCOPF problem will be very large, and its numerical solution will have great difficulties. Practical value

How to improve the efficiency of solving the SCOPF problem is the key to its practicality, and the existing methods cannot perfectly solve this problem

The Benders decomposition method, parallel computing technology and special sparse matrix processing technology have all been studied and used to improve the solution speed of SCOPF problems, but with the expansion of the expected fault set, the difficulty of solving the problem will increase exponentially; the expected fault screening method By filtering the expected failure set, only the reliability constraints of some critical failures are considered to reduce the size of the expected failure set

Since it is difficult to give an accurate key fault set at one time, this method generally needs to perform multiple key fault set screening through loops, and perform multiple SCOPF calculations for key fault sets, and its calculation efficiency is still low

In addition, if the scale of the fault set at the optimal solution of the SCOPF problem is large, the scale of the key fault set after screening is still large, the solution efficiency of the SCOPF problem may be very low, and there are still great difficulties in applying it to large-scale power systems

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